Your best bet is to study the Blue (Service Support) and Red (Service Delviery) Books, as well as to supplement it with other texts now available through many locations. You will only best examined on the ten core disciplines (cover in the Red/Blue Books).

In the US, you can take the exam at Prometrics locations (use web or phone book to find a local outlet). Most training providers want you to attend their class. Cost of the exam I believe is around US$ 200-250. 40 multiple choice questions.

However, by taking this route you will be missing some valuable interaction with others that can provide insight to the challenges and benefits of implementing Service Management.